This application claims the benefit of Japanese Patent Applications No. 2001-257221 filed Aug. 28, 2001, No. 2001-307144 filed Oct. 3, 2001 and No. 2002-201774 filed Jul. 10, 2002, in the Japanese Patent Office, the disclosures of which are hereby incorporated by reference.
1. Field of the Invention
The present invention generally relates to ink-jet recording apparatuses and copying machines, and more particularly to an ink-jet recording apparatus which has ink-jet nozzles arranged to cover the entire width of a recording medium and is provided with a reliability maintaining mechanism, and to a copying machine which uses such an ink-jet recording apparatus.
2. Description of the Related Art
An ink-jet recording apparatus carries out a recording operation by ejecting and adhering ink on a recording surface of a recording medium such as paper. Such an ink-jet recording apparatus is popularly used. Generally, the ink-jet recording apparatus is provided with a recording head having an ink-jet nozzle forming surface for ejecting the ink with respect to the recording surface of the recording medium.
For example, the recording head ejects ink drops by a pressure of an electro-mechanical converter or, by a heating energy of an electro-thermal converter, which is controlled based on a driving control signal supplied to the recording head depending on the image data. The ink is ejected with respect to the recording surface of the recording medium via the ink-jet nozzle forming surface of the recording head. In order to increase the recording speed, a plurality of ink-jet nozzles are arranged at the ink-jet nozzle forming surface of the recording head, that is, a multi-nozzle recording head. For example, the ink-jet nozzles are arranged at a relatively high density of 400 dpi to 600 dpi or, arranged to cover the entire recording region on the recording medium, such as the entire width of the recording medium.
In the multi-nozzle recording head of the latter type, the number of ink-jet nozzles (or orifices) is extremely large and is on the order of several thousand to several ten thousand. Hence, the probability of a nozzle clogging for such a multi-nozzle recording head is considerably large compared to that of a recording head only having several tens of ink-jet nozzles. However, the development of countermeasures against the nozzle clogging caused by the considerably increase in the number of ink-jet nozzles has recently just started, and no definite and effective means have yet been proposed. In addition, when the multi-nozzle recording head of the latter type having the extremely large number of ink-jet nozzles is applied to color recording, the number of such multi-nozzle recording heads used will increase, but countermeasures against the nozzle clogging in a plurality of multi-nozzle recording heads when carrying out the color recording have yet to be proposed.